Rolleiflex Repair Question

I recently picked up a very battered and dirty Rolleiflex at a local carboot sale, more of a heart than a head buy but I thought at least it could come home with me and be loved. It was extremely dirty but the shutter worked and the glass looked salvagable. I've worked out that it is an Old Standard 620 model with the Zeiss f4.5 lens. It is on the work bench now, the leather has been taken off the sides and cleaned ready for reglueing, the lenses have been cleaned and refitted (the taking lens is useable, the viewing lens is scratched but still clear enough for focussing), the mirror and ground glass have been cleaned and everything is looking hopeful for a working camera coming off the bench. I'm only cleaning the body not repainting so it will look very much as found.
Two problems though. Firstly, I think the camera has been taken apart before (marks on screw heads etc) and one of the screws holding on the front panel is missing. I am presuming it is a metric screw fitting but does anyone know of somewhere that would sell similar screws in the UK or is it a matter of going through the bodies of dead cameras until I find a match. Second, the clip holding the back closed is missing, I could tape the back shut but was hoping someone on the forum might have an old standard and could post pictures of how the clip looks so I could possibly look at making one from a strip of brass.
Regards
Matty

Download the Rolleiflex repair manual at http://www.kyphoto.com/classics/repairmanuals.html Follow the instructions at the top of the page. Although your model is not specifically listed the build of yours will be similar to those models that are.
Do a search for Miniature Metric Screws from your location as search engines have become location specific.
Take a digital caliper https://www.ebay.co.uk/sch/i.html?_...aliper.TRS0&_nkw=digital+caliper&_sacat=46576 and measure the outside of an existing screw or the inside of the screw hole and look up that dimension in a metric screw thread chart, should be easy to find on line. Most small metric screws have only one thread pitch so choose the closest dimension to what you measured. Camera manufactures occasionally had a special screw made in which case you have to find a surplus original or rob from another body.

Here are some fine photos of the clip for the back:

https://www.kameratori.fi/rollei-rolleiflex-old-standard-35-model-622-en_1

Enjoy that camera, I have had two of the Old Standards and they are a lot of fun once they are fixed up to shoot. I have been trimming down the collection so kept my original model. You can find third party lens hoods to help with contrast and overall image quality.